Eye Health Guide · ORINvue

Colour Blindness (Colour Vision Deficiency)

Hindi / common name: Colour Blindness (rang andhapan / rang na pehchaan paana)

By ORINvue, Lucknow · Updated 2026-10-14 · Information only, not medical advice

Colour blindness, or colour vision deficiency, means difficulty telling certain colours apart, most commonly reds and greens. Most people with it see colours, just differently, and true total colour blindness is very rare. It is usually inherited and present from birth, and many people only discover it during a school, job or medical test. It does not get worse in inherited cases and does not affect sharpness of vision.

Symptoms of Colour Blindness

• Difficulty telling red, green, brown and orange apart
• Confusing blue and purple, or blue and green (less common type)
• Colours looking dull or washed out
• Trouble reading colour-coded charts, maps or wires
• In children: difficulty learning colours, or using unusual colours in drawings
• Very rarely, seeing only shades of grey with light sensitivity and poor vision

Causes and risk factors

• Inherited (genetic) red-green deficiency passed on the X chromosome, so it is far more common in males
• Inherited blue-yellow deficiency (rare)
• Acquired causes: optic nerve diseases, glaucoma, cataract, macular disease and diabetes
• Some medicines, such as ethambutol used for tuberculosis
• Chemical exposure and head injury

How it is diagnosed

Colour vision is commonly screened with Ishihara plates, a booklet of coloured dot patterns with hidden numbers. Further tests such as arrangement tests or an anomaloscope can classify the type and severity. Any colour vision change that appears in adult life, especially in one eye, should be checked by an ophthalmologist because it can signal an underlying eye or nerve problem.

Treatment options

• Inherited colour blindness has no cure
• Special tinted lenses or filters can increase contrast between some colours for some people, but they do not restore normal colour vision
• Phone apps and accessibility settings can help identify colours
• Acquired colour vision loss is managed by treating the cause, under an eye doctor

Glasses and lens options

Colour-enhancing tinted spectacles may make some colours stand out more for certain people, and some find them enjoyable outdoors. They do not cure colour blindness and should not be used to try to pass a colour vision test. Ordinary prescription lenses are made as normal.

Prevention and everyday care

• Inherited colour blindness cannot be prevented
• Screen children's colour vision early so teachers and parents can support learning
• Check colour vision before choosing careers that require it
• Report any new change in colour vision to an eye doctor promptly

Colour Blindness in Lucknow

Students in Lucknow preparing for careers such as the armed forces, aviation, railways or some technical fields should check colour vision requirements early, before investing years of preparation.

Frequently asked questions about Colour Blindness

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